Welcome to the latest edition of Ask John where renowned rugby historian John Griffiths will answer any rugby-related query you have!

So, if there's something you've always wanted to know about the game we love but didn't know who to ask, or you think you can stump our expert - then get involved by sending us a question.

In this edition John answers questions on Magners League winners, Naas Botha's predecessor and Wales' youngest try scorer before Tom Prydie.

Who was Wales's youngest Test try-scorer before Tom Prydie?Anon

The youngest Welshman to score a Test try before Tom Prydie's effort against South Africa on Saturday was Tom Pearson, the Cardiff wing who crossed on his Test debut against England at Rodney Parade, Newport, on January 3rd, 1891.

Pearson was then 18 years and 238 days old. Keith Jarrett was 18 years and 332 days old when he scored his try (also on debut) for Wales against England at Cardiff in 1967.

Which players have won the most Magners League winners' medals?Michael O' Dwyer, Ireland

The Magners League was originally known as the Celtic League and started in 2001-02. The Ospreys, with their win against Leinster in the League Final on May 29th, became the first side to win the title three times.

Eight members of their winning side appeared in the club's three successful seasons in 2004-5, 2006-7 and 2009-10: Andrew Bishop, James Hook, Shane Williams, Paul James, Huw Bennett, Adam Jones, Jonathan Thomas and Ryan Jones. Hook, it should be noted, played only five minutes of Celtic League rugby in 2004-05, as a replacement against Cardiff Blues.

A ninth member of their side in this year's final, Lee Byrne, played for the Ospreys in the 2006-07 campaign and was a winner with Llanelli Scarlets in 2003-04.

Who did the legendary Naas Botha replace as Northern Transvaal (now Blue Bulls) fly-half way back in 1977?Gerhard Calitz, South Africa

Naas Botha began his first-class career with Northern Transvaal in 1977, succeeding J P (Joos) le Roux in the No.10 shirt.

Le Roux had been the regular fly-half for the province in the 1976 Currie Cup in which Northern Transvaal finished a disappointing third (behind Western Province and Natal) in Section One of the round-robin stage of the tournament. Western Province subsequently lost to the Section Two winners, Orange Free State, in that year's Currie Cup Final.

Le Roux's finest moment was in August 1976 when he kicked two conversions, two penalties and dropped a goal in Northern Transvaal's 29-27 victory at Loftus Versfeld against Andy Leslie's All Blacks. A fortnight earlier le Roux had landed 27 points in the province's 67-13 Currie Cup win against Rhodesia.

Le Roux was never awarded Springbok colours. Gerald Bosch was the Springboks incumbent at No.10 at the time. He lost his Test place to Western Province's Robbie Blair in 1977, Blair having impressed the Springbok selectors when playing against the young Naas Botha in WP's 16-14 home win against Northern Transvaal at Newlands in June 1977.

In his first season as a Blue Bull Botha was involved in their 41-26 spree against a strong World Invitation XV and guided them to a winning Currie Cup Final at Loftus Versfeld against Orange Free State in September. In 1977 he shared place-kicking duties with fullback Pierre Edwards who was employed for the longer-range kicks at goal.

How many teams have been coached by a former player who beat that team as a player? I know that, for instance, Warren Gatland was in the Waikato team that beat Wales in 1988.Paul Johns, New Zealand

Warren Gatland was Waikato's hooker in their 28-19 victory over Wales at Hamilton in the opening match of the 1988 tour. He is one of a small band of 2009-10 national head coaches who appeared as a player in a winning side against the team they now coach:

Scotland's current coach, Andy Robinson, played for England when they drew with Scotland at Twickenham in 1989.

I noticed a previous post regarding the history of jersey numbering. Are there any specific laws that this "must" be adhered to, or can teams (Super 14/15) break with tradition and have individual player numbers like soccer?David, Australia

The IRB took the lead regarding consistent jersey numbering back in 1967, prescribing for international matches the convention that still stands.

The only time when "squad" numbering was the vogue in rugby was during tours undertaken before 1967, when it was the norm for visiting players to wear their individual tour numbers, even during Test matches.

Below international level, clubs and provinces now follow bylaws that govern competitive rugby and fall in with the IRB's numbering convention. One consequence of this (relatively recent) change has been that there is no more alphabet soup when Bristol or Leicester club matches take place. Until recently both teams stuck to their age-old club conventions and wore letters.

What was the rule change that enabled defences to adopt the rugby league style defence we see these days?Peter Hughes, Wales

Not so much a rule change as a difference in emphasis led to this defensive aspect. It was the directive to referees to clamp down on the rucking of bodies that were lying on the wrong side of the ball that led to this feature of defensive play. With players reluctant to commit to rucks, the side taking the ball into the tackle found itself struggling to recycle possession quickly. Defences used the time and spare numbers to fan out rugby-league style across the field.

Dull rugby was a running sore for the first three-quarters of the season, before the Premiership took action from late March. Referees were instructed to adopt several measures designed to free-up the tackle area. Foremost (and most effective in wresting back the advantage to the attacking side) was the instruction that the tackler must immediately move away from the ball-carrier. Tacklers were instructed to release man and ball at the tackle before competing for it.

The upshot was that most agreed that matches played in April and May were far more entertaining and the stifling effects of defences were less evident.